Care homes giant Four Seasons has collapsed into administration, raising fears for thousands of elderly residents.
The company has appointed corporate undertakers at Alvarez & Marsal (A&M) to carry out the process following an aborted sale attempt.
Four Seasons houses 22,000 elderly residents across 322 homes, although the firm insists that operations will be unaffected by the move.
It currently operates homes across Derbyshire and Nottinghamshire.
A Four Seasons spokesman said: "The operating companies under which the care home and hospital operations sit are not in administration and continue to be run as normal by the existing leadership teams."
The collapse is the biggest care homes failure since Southern Cross went bust in 2011.
Late last year, US hedge fund H2 Capital Partners, which effectively controls Four Seasons, ordered a sale of the crisis-hit company, which is struggling under a £525 million debt mountain. The bulk of the debt is held by H2, which is run by Spencer Haber.
Only weeks ago, Four Seasons insisted that it had "sufficient operating liquidity" to be able to complete the sale process.
A&M will now attempt to sell the group out of administration.
Dr Claire Royston, group medical director of Four Seasons, said: "Today's news does not change the way we operate or how our homes are run or prompt any change for residents, families, employees and indeed suppliers.
"Our priority remains to deliver consistently good care. It marks the latest stage in the group's restructuring process and allows us to move ahead with an orderly, independent sales process."
But the failure of Four Seasons caps a sorry saga for the group, which had been owned by Guy Hands' private equity vehicle Terra Firma.
Terra Firma bought Four Seasons for £825 million in 2012 and has been forced to stomach a £450 million writedown on its investment.
There have been acute worries over Four Seasons' financial performance and debt pile for several years.
It has been stung by a cut in local authority fees, rising costs and the introduction of the national living wage, and the group has continuously warned over its long-term stability.
Richard Fleming, of A&M, said: "We are committed to ensuring the group delivers continuity of care as we work to undertake the independent sales process.
"The group has continued to improve its quality ratings across their portfolio of homes and hospitals.
"The group's operations are fundamentally strong and a successful sales process will enhance those operations' ability to thrive."